1. Technical Field
The present invention relates to an image capturing optical lens system. More particularly, the present invention relates to a compact image capturing optical lens system applicable to portable electronic products.
2. Description of Related Art
In recent years, with the popularity of mobile products with camera functionalities, the demand of optical lens systems is increasing. The sensor of a conventional photographing camera is typically a CCD (Charge-Coupled Device) or a CMOS (Complementary Metal-Oxide-Semiconductor) sensor. As the advanced semiconductor manufacturing technologies have allowed the pixel size of sensors to be reduced and compact optical lens systems have gradually evolved toward the field of higher megapixels, there is an increasing demand for compact optical lens systems featuring better image quality.
A conventional and compact optical lens system employed in a portable electronic product such as the one disclosed in the U.S. Pat. No. 8,179,470, mainly adopts a four-element lens structure. Due to the popularity of mobile products with high-end specifications, such as smart phones and PDAs (Personal Digital Assistants), the requirements for smaller pixel size and better image quality have been increasing. However, the conventional four-element lens structure cannot satisfy these requirements of the compact optical lens system.
Although other conventional optical lens systems with five-element lens structure such as the one disclosed in the U.S. Pat. No. 8,000,030 enhance image quality and resolving power, it still reside with unsolved problems. Since the arrangement of the lens elements which are close to the image side of the optical lens elements is not proper regarding the refractive index, it is not favorable for obtaining more of the image coverage. Furthermore, it is also not favorable for keeping the optical lens system compact due to the size of barrel. Therefore, a compact optical lens system which can be applied to the portable electronic products with larger refractive index on the image side of the optical lens system and with more of image coverage under limited peripheral regions of lens elements is called for solving the problems stated above.